I did a search and couldn't find any similar problems, so here goes:

95 Bonneville SE (N/A) Stock 4T60E, 102,000 miles. Works perfectly except it won't upshift at WOT. Revs climb to around 5500 and then just hang there, until throttle is partially closed. Happens in first and second (haven't tried maxing out 3rd yet).

TCC is working fine, no codes on scanner, no leaks, fluid level OK.

What has been tried so far:
Replaced tranny fluid and filter (no excessive metal in pan, fluid wasn't burnt)
Replaced Modulator - no difference.

Any Ideas, or is it rebuild time?

TIA for any help.

Warren
Cincinnati OH
95 Bonneville SE - Unmodded daily driver

so are u saying that when the gear selector is in D its doing this or when you have the selector in 1, 2, and 3??

third gear will never go into TCC lock up at WOT

Thanks for the reply!!

Yes, it is doing it in Drive.

I hooked up the scanner on the way in this morning, and in first gear, the revs start increasing more slowly at around 5000, and if I don't let up on the throttle, they climb very slowly to around 5200. But I did not see any indication on the scanner that the tranny was trying to shift.

Perhaps the problem is not the tranny itself but in the signal to the transmission controller?

At what RPM should the tranny upshift from 1st to 2nd at WOT?

I will continue to scan and see what else I can find.

Sorry for the 20 questions, and thanks for the help.

Warren
Cincinnati OH
95 Bonneville SE - Unmodded daily driver

Need to get this clear.....during normal driving, you're ok? What RPM'* do you run at 55mph (cruise on, level ground) in OD?

Yes, during normal driving, everything is fine, just won't upshift at WOT.

RPM is around 1800 at 55mph in OD (cruise on, level ground). According to my OTC scanner (and how it feels), the Torque Converter clutch is functioning correctly, and it engages/disengages smoothly, so I don't think the problem is related to the TCC.

The speed sensor reads accurately according to the scanner, and all of the other data points in the scanner look reasonable.

There must be something obvious I'm missing, but I haven't had the opportunity to troubleshoot an electronically-controlled automatic before.

Thanks again,

Warren
Cincinnati OH
95 Bonneville SE - Unmodded daily driver

I don't think it'* rebuild time. If the PCM calls for a shift, and it doesn't happen, it should set a code. So for some reason, your PCM isn't calling for a shift.

Can you tell us the TPS voltages at idle and WOT? You can do this with the ignition on, car off. Just move the throttle by hand under the hood, or by foot in the car without the engine running.

The TPS voltages (Ignition on, engine not running-measured with foot on pedal to simulate actual driver input):

Throttle Closed: .39v
WOT: 3.91v (occasionally flickering to 3.93v)

Warren
Cincinnati OH
95 Bonneville SE - Unmodded daily driver

umm...that seems a little low on the WOT end

you want idle at about .71 and WOT at 4.35

Funny, as you were posting that, I was looking at the TPS mod page...Tomorrow I'll mod the TPS to get the higher voltages.

I'll post the results after I'm done.

Thanks for the help!!

Warren
Cincinnati OH
95 Bonneville SE - Soon to be TPS-Modded daily driver

OK, I replaced the TPS (just to be sure), modded it to get 4.35v at WOT, (Idle is around.66v), and put a 180 thermostat in it while I was there.

Now the car will not run. It cranks fine, and engine starts like normal, then IMMEDIATELY dies (stops right around the time I stop cranking).

I checked the following:
1. Codes: 1629 (this is a code that I had been getting before I touched the car, when it started and ran just fine), and an occasionat 0321 (which I had been geting intermittently before also).
2. Crank Sensor was replaced a month ago, and I verified that it is still working, the scanner shows RPM when cranking.
3. I can hear fuel pump prime, fuel pressure shows 48psi before cranking.
4. I am getting spark from all 3 coils, until it dies.
5. Fuel Injectors are firing (put a light on 2 of them and they lit up), until it dies.
6. Checked connectors were plugged in, and checked fuses.
7. Checked the pink wire going into the ICM, shows constant +12v when key is in Run or Crank position.
8. Unplugged Cam Sensor, car started a little harder, but it started then immediately died (same as before).
9. Tried different throtte positions, car always started. Revs were higher with more throttle, but engine died just as quickly.
10. Verified VATS system is working (checked both keys, security light comes on for a short period when key is turned to Run position, then goes out).
11. Disconnected battery for 1 hour to clear memory, still does it.
12. (Added) After the engine stops running, the Scanner shows VATS SYS switches from OFF to ON for a few seconds, then returns to OFF.

I'm stumped. Any wisdom on where to start (so to speak)?

Very frustrated...Thanks for any help you can give.

Warren
Cincinnati OH
95 Bonneville SE - Unrunning daily driver